Trees of the Mediterranean

Despite Portugal not directly bordering the Mediterranean Sea, the country is dominated by the temperate Mediterranean climate, typically characterised by hot, dry summers and cool, damp winters. This climatic diversity, with areas of greater or lesser Atlantic or continental in uence, has a visible e ect on vegetation cover. The scarcity of rain in summer and the relatively mild and dry climate encourages the growth of hardy, small-leaved trees such as the cork oak (Quercus suber). This unique oak, which is able to replace its bark – cork – following its extraction every nine years, a practice which would kill any other tree, occurs naturally in almost every part of Portugal. Known by various names in Portuguese, the cork oak can grow up to twenty metres high and live for more than 150 years, creating wild woods (sobreirais) and dense forests which are very useful for silvopasture (montados), both of which are extremely important for nature conservation.

On the edges of woods and cork oak forests as well as in clearings, another Mediterranean tree of rather more limited distribution can be found – the Iberian pear (Pyrus bourgaeana). It is a small wild pear tree, with almost spherical pears of a greenish or yellowish colour, which provide food for various birds and mammals during autumn. While the bitterness and brous pulp of its fruits do not invite human consumption, the tree’s wood and its capacity for grafting with other pear or apple trees is highly valued.

In more open areas of the montados and in mixed woods, another typically Mediterranean tree can be found, the strawberry tree (Arbutus unedo), which can also form purer woods – the medronhais. The strawberry tree has a aky, reddish trunk, grows up to ve to ten metres high and can live up to 200 years. In autumn, its bright green, serrated edged leaves contrast vividly with its yellow or reddish fruit, which provide the wild species with precious reserves before winter comes, and are also used in several Portuguese regions to make confectionery and to distil the typical medronho brandy.

But of all the Mediterranean trees, the olive tree (Olea europaea) is the best known, due to its abundant cultivation and the excellent quality of the oils produced in many regions of Portugal, including several Protected Designations of Origin (PDO). Curiously, the olive tree is not native to Portugal, but originated instead in the Near and Middle East and was later spread across the entire Mediterranean basin by the Phoenicians and Romans for olive cultivation and oil production. These trees with a broad, round crown do not grow more than ten to fteen metres high, but they can have an enviable longevity of up to 2,000 years. In nature, the wild strain – the wild olive – can grow in high bushland and mixed forests or, in a purer manner, forming wild olive groves. Besides producing olives and oil, olive trees are also valued today for the pronounced originality of their twisted trunks, becoming ever more popular in landscaping.

For the third consecutive year, the Postal Services of Portugal are participating in this initiative from the Postal Union for the Mediterranean (PUMed), choosing to display four typical examples of Portuguese Mediterranean ora on this set of stamps, from widely known and purposefully cultivated species such as the olive tree and cork oak, to more discreet species such as the Iberian pear, and wild species such as the strawberry tree.